Sharif Digital Repository

Catalytic esterification of acetic acid with 1-hexanol was investigated over polyoxometalates. H3PW12O40 and H3PMo6W6O40 polyoxometalates with keggin structures were synthesized. Catalytic activity and recyclability of them were improved by loading on the γ-Al2O3 with impregnation method and Cs, K and NH4 salts preparing.Catalysts were characterized by XRD, SEM, FT-IR, BET, DRS and NMR techniques. According to XRD's results, catalysts have ace-centered cubic crystal systems. Loading on supports and preparing the salts do not destroy the structures of polyoxometalates. SEM images show the uniformity of catalysts' surface and catalysts' fixing on the support. It was seen that the keggin... 

Ionic liquids due to their unique physical and chemical properties are widely used in various fields of chemistry and chemical engineering. Determining properties of ionic liquids can be difficult, time consuming or even impossible. In first step of this study the IL thermo database was chosen as source of experimental data of ionic liquids. Viscosity, density, surface tension and melting temperature of ionic liquids based on bis(trifluoromethylsulfonyl)imide anion with cations imidazolium, pyridinium, pyrrolidinium, piperidinium and ammonium were modeled using QSPR approach. Linear and nonlinear models were built by means of multiple linear regression (MLR), multilayer perceptron neural... 

Thermodynamic quantities such as proton affinity (PA) and molecular basicity (GB) for (CaO)n nanoclusters with n=2–16 have been calculated using three computational models of the DFT (B3LYP, M06, PW91, CAM–B3LYP and ωB97XD functionals), MP2, and HF with the cc-PVNZ (n = D and T) basis set in the gas phase. Absolute deviation error (AAD%) indicates that obtained PA and GB values using DFT model and the B3LYP method with mean percentage errors of 0.77 and 0.90 %, respectively, have the higher accuracy than the other methods and models. Owing to the unique physical and chemical properties of ILs, can be used as catalysts, promoters and modifiers of catalyst in many organic reactions. Therefore,... 

The use of energetic ionic liquids as hypergolic fuels, has low toxicity and environmental risk relative the hypergolic fuels such as the hydrazine. In this research by using Gauss view and Gaussian softwares and density functional theory and MP2 methods at the level of B3LYP/6-311G(d,p), the proton transfer from the cations to anions for a set of hypergolic ionic liquids in the gas and solution phases were studied. The most stable configuration of cations and anions are determined. The interaction energies of the selected cations and anions, proton affinities and basicity properties of these hypergolic anions are calculated. The result represents that the lower proton affinity and basicity... 

Nanocomposite FeVO4/CeO2 was synthesized by hydrothermal method and was applied for removal of methyl orange. This nanocomposite was characterized by SEM, FT-IR, XRD, BET methods. SEM images showed that FeVO4 nanorode decorated on CeO2 spherical particles. The results of XRD patterns confirmed the triclinic structure for Fe(III)vanadate and the cubic fluorite structure for cerium oxide. The surface area of FeVO4, CeO2 and FeVO4/CeO2 was determined by BET analysis which the results represented an increase in surface area in nanocomposite using cerium oxide as support. The electro-Fenton reaction was performed in undivided electrochemical reactor using stainless steel electrodes and the... 

In this project, metal oxides loaded on different supports were used in the heterogeneous electro-Fenton (EF) process for organic pollutants removal. At first, Fe3O4/AC was synthesized for catechol degradation as a phenolic compound. 98.2% removal of catechol was achieved by operational conditions optimization. The catalytic activity of Fe3O4/AC was remained constant after 6 cycles. In the other study, reduced graphene oxide was used as a support for the magnetite nanoparticle catalyst. The catalytic activity of Fe3O4/rGO in EF degradation of reactive red 195 (RR195) dye was studied and 93.34% removal was obtained. Response surface methodology (RSM) was used and a quadratic model with... 

Phenolic compounds, which are one of the most dangerous compounds for the environment, are present in many effluents of various industries such as petrochemicals and pharmaceuticals, and the need to eliminate these compounds is increasingly felt. In this study, adsorption of three compounds of para-chlorophenol, para-nitrophenol and hydroquinone on polypyrrole adsorbent in the form of neutral, charged, copolymer with polyaniline and phosphorus-doped have been investigated using density functional theory (DFT). Calculations are performed at two levels of b3lyp/6-31+G(d,p) and wb97xd/631+G(d,p) for two different orientations of adsorbate molecules that the correlation-exchange function wb97xd... 

In this project, BiVO4 , Mn3O4 and BiVO4- Mn3O4 nanocatalysts were synthesized using the hydrothermal method. The properties of these nanocatalysts were determined by XRD, SEM, FT-IR, DRS, PL, ICP, EDX, BET and AA techniques. Analysys XRD patterns and SEM images of samples confirmed monoclinic structure for BiVO4 and tetragonal structure for Mn3O4. The DRS and PL spectra showed adctrease in the band gap and electron – hole pair recombination for BM 60:40 relative to BiVO4. Oxygen production was studied in the presence of different percentages of BiVO4 and Mn3O4 in BiVO4 - Mn3O4 nanocomposite and was observed that the 60:40 wt.% (Bismuth vanadate 60% and manganese oxide 40%) produced more... 

In this study, CoFe2O4/CuO nanocomposite was synthesized by hydrothermal method and utilized for removal of metronidazole in electro-Fenton process. Nanocomposite was characterized by FT-IR, XRD, FE-SEM, VSM and BET methods. The Results of XRD patterns confirmed the monoclinic structure formation for copper(Ⅱ) oxide and the spinel structure for CoFe2O4. The FE-SEM images displayed the formation of CuO nanosheets for copper(Ⅱ) oxide and the decoration of cobalt ferrite nanoparticles on the surface of CuO nanosheets. Measurement of the surface area of nanocatalysts using BET isotherm represented the high surface area for CuO nanosheets and the increase of surface area of nanocomposite in... 

Today, fossil fuels cause countless environmental pollutants, so replacing fossil fuels with clean energy sources is very important. Water splitting using light and a semiconductor is one of the new methods of producing oxygen and hydrogen, which due to its simplicity and cheapness, has attracted a lot of attention today. In this study, ZnMn2O4 photocatalyst nanoparticles were first loaded on a graphitic carbon nitride support in different ratios of ZnMn2O4 and carbon support by hydrothermal method. Then the photocatalysts were evaluated for evolution of oxygen and hydrogen photocatalysts through water splitting under visible light. In ZnMn2O4 / g-C3N4 (80:20) nanocomposite, the highest... 

In this project photocatalysts TiO2, H3PW12O40, H3PMo6W6O40, H3PW12O40 / TiO2, H3PMo6W6O40 / TiO2, K2.5H0.5PW12O40, Cs2.5H0.5PW12O40, (NH4) 2.5H0.5PW12O40 and H3PW12O40 / M-TiO2 that M = La , Ce, Cr, Fe, Co were characterized by techniques DRS, FT-IR, BET, 31P NMR, SEM and XRD. The results of SEM and XRD particle size and page crystalline nanoscale catalysts, with size less than 40nm, respectively. FT-IR analysis confirmed the structure of heteropolyacid was produced. DRS analysis of the degradation reactions during wavelenght longer upheld. Degradation of methylene blue and pollutants such as Tinopal CBS-x to the polyoxometalates keggin is homogeneous and composite titanium dioxide two... 

In this research, BiFeO3/Bi2WO6 nanocomposite was synthesized by hydrothermal method and utilized for piezocatalytic degradation of methyl orange dye. This nanocomposite was characterized by XRD, FE-SEM, FT-IR, DRS, PL and Raman spectroscopy. The results of XRD patterns confirmed the rhombohedral crystal structure of BiFeO3 nanoparticles and orthorhombic crystal structure of Bi2WO6 nanosheets. FT-IR and Raman spectroscopy approved the existence of chemical bonds and non-centrosymmetric structure of catalysts. The FE-SEM images displayed the formation of BiFeO3 nanodisks and the Bi2WO6 nanosheets and the decoration of BiFeO3 nanodisks on the Bi2WO6 nanosheets. By using the data of DRS... 

In this research, piezocatalysts ceramics Bi4Ti3-xMnxO12 (x=0,0.1,0.2,0.3) were synthesized by hydrothermal method and utilized in the process of rhodamine B piezocatalytic degradation.These piezocatalysts were characterized using XRD, FE-SEM, FT-IR, DRS and PL methods. The results of XRD patterns confirmed the formation of orthorhombic crystal structure of Bi4Ti2.9Mn0.1O12 and Bi4Ti3O12 piezocatalysts. FT-IR spectroscopy confirmed the existence of chemical bonds of piezocatalysts. FE-SEM images showed the formation of Bi4Ti2.9Mn0.1O12 and Bi4Ti3O12 nanoplates. Using DRS analysis data, the absorption edge wavelength and energy gap of the synthesized piezocatalysts were obtained. Also, the... 

The emission of carbon dioxide gas is one of the environmental problems in the world and the elimination of CO2 receives more attention by researchers day to day. In this study ,adsorption of carbon dioxide on fullerenes adsorbents such as C26, C32, C36, C38and C44 in the absence and in the presence of electric field and also on nitrogen-doped fullerenes such as C25N, C31N, C35N, C37N and C43N in the absence and in the presence of electric field were investigated. Calculations were performed using density functional theory at the level of B3LYP/6-311++G(d,p). The computations represent that doping with nitrogen has not effect considerably on adsorption of carbon dioxide and applied electric... 

The present work is based on the, synthesis and investigation of photocatalytic activity of TiO2, TiO2/MWCNT, ZnO and ZnO/MWCNT nanostructures. The nanostructures were prepared using multi-walled carbonnanotubes (MWCNT) as templates.The SEM images of TiO2 and ZnO nanoparticles and TiO2/MWCNT andZnO/MWCNT showed that nanosize TiO2 and ZnO particles homogeneously and densely supported on the surfaces of multiwall carbon nanotubes the photocatalytic activity of the TiO2, TiO2 /MWCNT, ZnO and ZnO/MWCNT was examined by the degradation of Basic Blue 41(BB41) under UV and Vis lights. The optimum conditions for degradation of BB41 on TiO2 where found to be: calcination temperature (450 °C), dye... 

The susceptible light-harvesting and tremendous reduction capability along with the potentiality (photo)electrochemical merits of the thiospinels like CuCo2S4 (CCS) bring forth appreciably an advancement in efficacious photocatalytic reactions. However, scant oxidation potential originated from 3p orbitals of sulfur atoms puts a damper on their performance and is even conducive to self-oxidation. In this research, the surfactant/template free of hierarchical CCS thiospinels was synthesized using solvothermal sulfidation of the affordable glycerate-based CuCo-alkoxide and successfully was embedded with Z-scheme V2O5 deposited on wrinkled g-C3N4 lamella (VO-UCN) in the interest of developing... 

TiO2, Ag/TiO2 and AgBr/TiO2 synthesized by sol – gel method. Synthesized samples were characterized by X- Ray diffraction (XRD) , Fourier transformed infrared ( FT – IR) , Scanning electron microscopy ( SEM) techniques. The results of XRD showed that the particle size is in the nanorange and anatase form of titania is present in all of the photocatalysts. Kinetics of photocatalytic degradation of an azo dye (Acid Orange 7) on photocatalysts was studied. The effect of various parameters such as dye concentration, amount of photocatalyst( AgBr/TiO2) and pH of solution on the rate and efficiency of degradation of Acid Orange 7 was studied. The optimized conditions ( [AgBr/TiO2]= 100 ppm,... 

Bismuth Vanadate (BiVO4) nanoparticles were prepared from two different precursors by precipitation method. The samples were characterized by Fourier transformed infrared (FT-IR), X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and BET. The photocatalytic activities were examined by degradation of Acid Blue 92 under visible light. The results revealed that all the BiVO4 samples were in a monoclinic phase in nano range. The photocatalytic activity of BiVO4 depend on the calcination temperature and the concentration of photocatalyst. The photocatalytic activity increases with the amount of catalyst loading and decreases with increasing the... 

With the development of urbanization, industrialization, explosive population growth, and environmental degradation, the world is facing a serious challenge of water pollution. Nowadays, the water-soluble pollutant such as heavy metals and dyes brought a serious threat to the aquatic organisms and human health due to their non-degradability and carcinogenicity.With the purpose of future security and to restore ecological balance, it is essential to give much significance towards the removal of unwanted toxic contaminants from water resources. In this regard, the removal of toxic pollutants from wastewater using Metal-organic frameworks (MOFs) -based composites is considered as one of the...